/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.google.code.motoo.codec.textline;

import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;

import com.google.code.motoo.codec.CumulativeProtocolDecoder;
import com.google.code.motoo.codec.ProtocolDecoderOutput;
import com.google.code.motoo.core.IoBuffer;
import com.google.code.motoo.core.IoSession;

/**
 * 
 * @author linfengqi
 * @version 1.0  May 13, 2009
 */
public class TextLineDecoder extends CumulativeProtocolDecoder {
	
	private CharsetDecoder decoder;
	private byte[] delimit;

	public TextLineDecoder(Charset charset, LineDelimiter decoderDelimiter) {
		this.decoder = charset.newDecoder();
		this.delimit = decoderDelimiter.getValue().getBytes();
	}

	public TextLineDecoder(Charset charset, String delimiter) {
		this(charset, new LineDelimiter(delimiter));
	}

	public boolean doDecode(IoSession session, IoBuffer in, ProtocolDecoderOutput out)throws Exception {
		if (in.hasRemaining()) {
			int initPosition = in.position();
			while(in.hasRemaining()) {
				byte b = in.get();
				if (b == delimit[0]) {
					int position = in.position();
					boolean match = true;
					for (int i = 1; i < delimit.length; i++) {
						if (delimit[i] != in.get()) {
							match = false;
							break;
						}
					}

					if (match) {
						int size = position - initPosition - 1;
						ByteBuffer message = ByteBuffer.allocate(size);
						byte[] source = in.array();
						message.put(source, initPosition, size);
						message.flip();
						CharBuffer charBuffer = decoder.decode(message);
						out.write(charBuffer.toString());
						return true;
					} else {
						in.position(position);
					}
				}
				
			}
		}
		return false;
	}

	public void dispose(IoSession session) throws Exception {
		decoder = null;
	}

	public void finishDecode(IoSession session, ProtocolDecoderOutput out)
			throws Exception {

	}

}
